• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.17 no.4
• /
• pp.347-354
• /
• 2005

This paper compared vertical temperature distribution between the existing balcony model without ventilator facilities and the improved balcony model with ventilator facilities using differential equation. As the air inside of balcony is heated by solar radiation this heated air is not exhausted in the existing balcony, remaining stagnant. The air temperature distribution was $26.7{\sim}29.3^{\circ}C$ in balcony without natural ventilator system. This heated air affected the rising air temperature of adjacent spaces such as living room and bedroom in the existing balcony. But, as the heated air inside of the improved balcony model is exhausted through natural ventilator facilities in summer, the air temperature in balcony has fallen. The air temperature distribution in improved balcony was $24.8{\sim}26.7^{\circ}C$ for the inlet air speed of 1 m/s and $24.6{\sim}26.7^{\circ}C$ for the inlet air speed of 3 m/s. The energy consumption of the improved balcony is 2.5 times less than of the existing balcony. The improved balcony with the closed damper makes a roll as the existing balcony in the aspect of the heating effect. When the heated air in the improved balcony is supplied, the air temperature is raised and the ventilation effect in adjacent spaces was improved.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.21 no.1
• /
• pp.41-47
• /
• 2015

The objective of this study was to evaluate quality properties including acid value (AV) and peroxide value (POV) of brown rice packaged with antioxidant allyl mercaptan sachet or oxygen scavenging sachet. To prepare the antioxidant allyl mercaptan sachet, allyl mercaptan was encapsulated by rice flour and put in small roll paper pouch. The oxygen scavenging sachet consists of diatomite, sodium L-ascorbate and activated carbon. The results of this study showed that antioxidant allyl mercaptan sachet had no antioxidant effect on deterioration of brown rice, but oxygen scavenging sachet effectively inhibited rancidity of brown rice. Therefore, the developed oxygen scavenging sachet can be effectively utilized in food packaging system for quality stability.

• Transactions of Materials Processing
• /
• v.27 no.1
• /
• pp.12-17
• /
• 2018

This paper outlines the research findings on the microstructure and mechanical properties of AZ31 Mg alloy fabricated by differential speed rolling (DSR) with respect to processing variables such as temperature, roll speed ratio (RSR), and deformation route. The resultant microstructure of the sample, deformed by 2-pass DSRs at 473 K, comprised finer grains with more uniform distribution than those at 573 and 623 K. This was due to active recrystallization, which was expected to appear during DSR at temperatures higher than 573 K. When the sample was deformed via DSR with RSR of 1:4 for the upper and lower rolls at 453 K, the values of yield and ultimate tensile strength were observed to be higher than their counterpart with RSR of 1:1. The application of sample rotation around the longitudinal axis would give rise to an excellent combination of tension strength (~330 MPa) and ductility (~20 %) at ambient temperatures. This is discussed based on its uniform fine grained structure and the softening of basal texture.

• Transactions of The Korea Fluid Power Systems Society
• /
• v.7 no.4
• /
• pp.32-38
• /
• 2010

A semi-active suspension is an automotive technology that controls the vertical movement of the vehicle while the car is driving. The system therefore virtually eliminates body roll and pitch variation in many driving situations including cornering, accelerating, and braking. This technology allows car manufacturers to achieve a higher degree of both ride quality and car handling by keeping the tires perpendicular to the road in corners, allowing for much higher levels of grip and control. An onboard computer detects body movement from sensors located throughout the vehicle and, using data calculated by opportune control techniques, controls the action of the suspension. Semi-active systems can change the viscous damping coefficient of the shock absorber, and do not add energy to the suspension system. Though limited in their intervention (for example, the control force can never have different direction than that of the current speed of the suspension), semi-active suspensions are less expensive to design and consume far less energy. In recent time, the research in semi-active suspensions has continued to advance with respect to their capabilities, narrowing the gap between semi-active and fully active suspension systems. In this paper we are studied the characteristics of vehicle movement during the field test with conventional and semi-active suspension system.

• Aerospace Engineering and Technology
• /
• v.5 no.2
• /
• pp.240-247
• /
• 2006

Tilt rotor aircraft is a multi-configuration airplane which has three independent flight modes; helicopter, conversion, and aiplane. The control surface mixer resign is reqctired to generate and distribute efficient control forces and moments in each flight mode. In the conversion mode, the thrust vector is changed from helicopter mode to airplane, therefore the thrust vector makes undesired forces and moments which affect on pitch, roll and yaw dynamics. This paper describes the design results of control surface mixer design which minimize the undesired forces and moments due to nacelles tilting angle change for 4O% scaled model.

• Culinary science and hospitality research
• /
• v.12 no.4 s.31
• /
• pp.116-130
• /
• 2006

This research was accomplished to analyze the preference and the actual using patterns of the bakery products using functional ingredients by subjects' age. This survey was examined by the self-administered questionnaire method for 374 female subjects in Suwon. All respondents preferred breads than confectionaries with functional ingredients. As for the products of cooking ingredients, cookies, roll-cake, cake, chocolate, the preference of teenagers was higher than those of the other groups. Subjects preferred potatoes, fruits, rice and green tea as functional ingredients. Over thirties showed the high preference over beans, vegetables, mushrooms, ginseng and oriental herbs while fruits were highly preferred in teenagers and twenties. The ratio of using the bakery products with functional ingredients once or twice a week was higher in over thirties than those of the other groups. Subjects answered that they generally spent $3,000won\sim5,000won$ on those products. Functionality of products was considered as the more important factor in thirties than in the other groups. The lack of information about these products and functional ingredients was reported by teenagers and twenties. These results would be basic data for marketing or improvement of baking products with functional ingredients.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.10 no.1
• /
• pp.25-30
• /
• 2010

This paper is proposed about three axis motion control camera design method based on wires. Original motion control camera consists of track, boom, L-Head, Camera and so on and is enormous and expensive. But proposed motion control camera adjusts wire length using encoders and motors. And position control use position based straight line of straight-line move method for moving precise position. Proposed simple design is able to use various place and inexpensive than original motion control camera. But, camera was vibrated and rotated due to basic property of wire. So we proposed solutions that connected method of wire and using a tensional object for reducing rotation. For proposed algorithm verification, we realized three axis motion control camera based on wire and measured oscillation while moving same trace. We confirmed the results that standard deviation of oscillation was reduced 4.93 degree than before design method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.27 no.2
• /
• pp.104-109
• /
• 2014

To operate organic light emitting device (OLED) with alternating current (AC) power source without AC/DC(direct current) converter, we fabricated the fluorescent OLED and measured the emission characteristics with AC and DC. The OLED operated by AC showed higher maximum current efficiency of 8.2 cd/A and maximum power efficiency of 8.3 lm/W. But current efficiency and power efficiency of AC driven OLED showed worse than DC driven OLED at high voltage above 10 V. This result can be explained by the peak voltage of AC was $\sqrt{2}$ times than DC, In case of low driving voltage the emission characteristics were improved by the peak voltage of AC, but in case of high driving voltage the emission efficiencies were decreased by the roll off phenomena. Finally, serial OLED arrays using twelve OLEDs driven by AC 110 V showed average voltage of 9.17 V, voltage uniformity of 99.0%, average luminance of $1,175cd/m^2$, luminance uniformity of 94.4%.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.7 s.361
• /
• pp.16-23
• /
• 2007

For a fully depleted SOI type symmetric double gate MOSFET, a simple expression for the threshold voltage has been derived in a closed-form To solve analytically the 2D Poisson's equation in a silicon body, the two-dimensional potential distribution is assumed approximately as a polynomial of fourth-order of x, vertical coordinate perpendicular to the silicon channel. From the derived expression for the surface potential, the threshold voltage can be obtained as a simple closed-form. Simulation result shows that the threshold voltage is exponentially dependent on channel length for the range of channel length up to $0.01\;[{\mu}m]$.

• Journal of the Society of Naval Architects of Korea
• /
• v.48 no.1
• /
• pp.8-14
• /
• 2011

RIB(Rigid Inflatable Boat) is widely used for coastal transportation in the commercial use and for ISR(Intelligence, Surveillance, Reconnaissance) in the military use. Since RIB is around 10 meters in length and over 30 knots in speed, its motion characteristics in waves is quite different from a large scale ship. When it turns, large roll occurs and heeling direction is opposite to the large ship's case. Currently, many countries are developing USV(Unmanned Surface Vehicle) of which type is RIB. In order to develop high performance autopilot and way point controller, it is very important to identify RIB's motion characteristics. In this paper, sea trial test results of a 7-meter RIB such as speed, turning, zig-zag, and way point control tests were represented and its resistance and propulsion model was identified by using sea trial data and Savitsky's formula. In addition, the state space model which will be used in the identification of the four-degree-of-freedom dynamics in the next step was formulated and the identification procedure was proposed.